1. Field of the Invention
The invention relates to a scaffolding component having at least one connection head for formation of a releasable connection, particularly of a connection node, with a vertical scaffolding element that extends in the direction of a longitudinal axis, onto which element a projection that extends transversely, in other words in a transverse direction, relative to the longitudinal axis of the scaffolding element, and has a recess in the form of a perforation for inserting a wedge through it, is fastened, and whereby the connection head has an upper head part having an upper wedge opening, and a lower head part having a lower wedge opening, for the wedge that can be inserted through the wedge openings, and whereby a slot that is open toward the front is disposed between the upper head part and the lower head part, for mounting the connection head onto the projection, particularly in an essentially horizontal mounting direction, and whereby the slot is delimited toward the top and toward the bottom with slot surfaces that extend on both sides of a horizontal center plane of the slot.
The invention also relates to a method for fastening a scaffolding component having at least one connection head onto a vertical scaffolding element that extends in the direction of a longitudinal axis, onto a projection that extends transversely, in other words in a transverse direction, relative to the longitudinal axis of the scaffolding element, and has a recess in the form of a perforation for inserting a or the wedge through it, whereby for formation of a releasable connection, particularly of a connection node, in which the connection head is locked in place, with shape fit, on the vertical scaffolding element, using the wedge that has been inserted through the opening, the scaffolding component with the connection head with its slot, or the connection head with its slot, is mounted onto or pushed onto the projection of the vertical scaffolding element, in an essentially horizontal mounting direction.
2. The Prior Art
From DE 24 49 124 A1, EP 0 423 514 A2, EP 0 276 487 A2, DE 198 06 093, and EP 0 936 327 A1, for example, scaffolding constructions having connection nodes of a modular scaffolding are evident, onto the posts of which perforated disks are fastened, spaced apart from one another, in the axial direction, in a grid dimension, in order to be able to connect scaffolding components in the form of connection, holding and/or support elements there, for example longitudinal bars, transverse bars and/or diagonals. Such a modular scaffolding has been known for many years as the LAYHER Allround scaffolding system. The connection nodes or scaffolding nodes of this modular scaffolding are also known under the designation LAYHER Allround force-transmitting node.
In these connection nodes, a particularly stable, releasable connection between the scaffolding components having connection heads, particularly rod elements such as scaffolding tubes or scaffolding bars, and the scaffolding posts provided with the perforated disks, is achieved. These connection heads have an upper head part and a lower head part and a horizontal slot that extends between them, which slot is open toward the front and to the sides. The upper head part has an upper wedge opening, and the lower head part has a lower wedge opening, for a wedge that can be inserted through the wedge openings. The wedge, which consists of flat material, particularly of steel, is undetachably connected with the connection head. For this purpose, the wedge has a retainer in the form of a rivet on its lower wedge end, which has rivet heads that project beyond the flat side surfaces of the wedge. Usually, a truss-head rivet or a blind rivet can be used. Preferably, the truss-head rivet can be riveted by machine, while the blind rivet can preferably be riveted by hand. The upper wedge opening of the upper head part is structured as a longitudinal slot having a slot width that is only slightly greater than the thickness of the wedge that is inserted through the upper wedge opening with its lower wedge end. The rivet projects laterally, with its rivet heads, beyond the wedge, with a rivet width that is greater than the slot width of the longitudinal slot of the upper wedge opening. As a result, the wedge cannot be pulled upward out of the connection head, but rather only up to an impact of the rivet heads on an inner delimitation surface of an upper wall part of the upper head part of the connection head. The lower wedge opening of the lower head part is greater than the upper wedge opening of the upper head part, specifically so great that the lower wedge end, with the rivet fastened there, can easily be inserted through the lower wedge opening.
For fastening the connection head to a perforated disk of a scaffolding post, the wedge is first, if this is not already the case, pulled upward in the vertical direction, and then pivoted toward the rear, in a direction toward an upper outer surface of the scaffolding component, particularly toward an upper outer surface of a rod element or scaffolding tube firmly connected with the connection head, for example of a scaffolding bar, preferably until the wedge lies against the said outer surface, so that the wedge is in an installation position in which it is shifted toward the rear. In this manner, the wedge remains in the said installation position during subsequent mounting of the scaffolding component with its connection head onto the perforated disk, in which position the connection head can be pushed onto the perforated disk, without any blockage by the wedge, in an essentially horizontal mounting direction, all the way into a mounting position, in which the wedge openings of the connection head are situated vertically above the perforated disk, so that subsequently, the wedge, after having been pivoted from the said installation position into a vertical introduction position, can move downward, as the result of gravity, specifically either immediately through a perforation of the perforated disk and through the lower wedge opening, into a locking position, or first onto the top side of the perforated disk, so that after subsequent displacement of the connection head on the perforated disk to a push-on position, in which the lower wedge end comes into alignment with a perforation of the perforated disk, the wedge can then move through this perforation and through the lower wedge opening, into a locking position, as the result of gravity. In the locking position, in each instance, the connection head is releasably locked to the perforated disk, with shape fit, to prevent unintentional release in all directions. Proceeding from this locking position, the wedge can be wedged in place by means of a hammer blow from above, onto its upper drive-in surface, in such a manner that the connection head is braced against the scaffolding post by way of the front contact support surfaces of its upper head part and its lower head part, which support themselves on the outer surface of the scaffolding post, and against the perforated disk by way of the wedge.
In practice, it is possible, in the case of specific ones of the aforementioned connection heads, not only to pivot the wedge, after it has been pulled out into an upper extraction position, in which the rivet impacts against the said inner surface of the upper wall part of the upper head part, toward the rear, into the said installation position, but also to pivot the wedge toward the front, into a position in which the upper wedge end projects beyond the connection head or its front contact support surfaces, toward the front. The wedge can remain lying in this position, pivoted toward the front, because of the lever conditions that occur, as the result of gravity, and as the result of friction forces, if the scaffolding component with the connection head is held in an essentially horizontal position. In this position, pivoted toward the front, the wedge is supported, on the one hand, on an upper wall part of the upper head part of the connection head, with a wedge face surface that is then a lower surface, on a front first support location, and is supported, on the other hand, on an inner rear second support location, by way of its rivet or by way of the rivet heads of the latter, on an inner wall of the upper head part of the connection head. It is furthermore possible, in practice, in the case of some of these connection heads, to support the wedge, when it is in such a position, pivoted toward the front, on or on top of an inner support crosspiece that delimits the upper wedge opening toward the rear and extends transverse to the mounting direction, with its lower wedge end, which is the rear wedge end in this position. This support crosspiece delimits the wedge accommodation space of the connection head toward the front, in order to prevent the wedge from slipping through downward when the connection head is not set onto a perforated disk and when the wedge has been inserted through the two wedge openings.
For the purpose of fastening the scaffolding components discussed above, according to the state of the art, with their connection head, onto a perforated disk of a vertical scaffolding element, positioning of the wedge as described above, which is possible in practice, in a position pivoted toward the front, before being mounted onto the perforated disk, is completely unsuitable. This is because in a case in which an attempt were to be made to fasten one of the connection heads known from the state of the art onto a perforated disk of a scaffolding post, in a manner usual in practice, in a position in which it projects beyond or in front of the connection head, toward the front, with its wedge, the wedge would fall downward with its lower wedge end, before the connection head has reached the perforated disk, as the result of gravity, after contact of the wedge with its upper, in this position front wedge end with the outer surface of the scaffolding post, and in the event of continued movement of the connection head, with the wedge projecting toward the front in this manner, in a radial direction, toward the scaffolding post, with the result that the wedge, which would then have fallen downward, crossing the horizontal slot, would block mounting of the connection head, with its slot, onto the perforated disk, and would therefore make it impossible. The result would be that continued mounting of the connection head, with the goal of subsequent locking of the connection head to the perforated disk, by means of the wedge inserted through a perforation of the perforated disk, would not be possible without previously pulling the wedge upward to above its slot. Aside from this, for this purpose the installer would have to be at a maximal distance limited by his personal reach, in other words in the vicinity of the perforated disk onto which the connection head is supposed to be mounted, in order to be able to pull the wedge upward there. This would make installation of the scaffolding components from a secured position impossible, or at least make it more difficult. Furthermore, the installer would have to undertake a new mounting attempt.
For this reason, in practice, the previously known scaffolding components, which are structured in the same manner or similar to what is disclosed in the documents mentioned above, are fastened onto the perforated disks with their connection heads, exclusively using an installation method during which, before the connection head is set onto the perforated disk, the wedge, as described above, is first moved into an installation position in which it is pivoted toward the rear, and in which method the scaffolding component, with its connection head with the latter's slot leading, is set onto the perforated disk in this installation position of the wedge, and in which method, after the connection head has been set onto the perforated disk, the installer must pivot the wedge manually back into a vertical position, while at a maximal distance from the perforated disk restricted by his personal reach or arm length, from which position the wedge can move into its locking position as the result of gravity. According to this previous method, no secured pre-assembly, particularly no leading railing, proceeding from a secure position of the installer, is possible with these previous scaffolding components.
From WO 97/27372 A, an arrangement for formation of a scaffolding node with a transverse strut and pillar has become known, from the outer surface of which at least one projection that projects radially relative to the pillar axis, in the form of a perforated disk having recesses, projects. A scaffolding component, for example a strut, can be fastened onto the perforated disk. The strut has a wedge-shaped hook on at least one of its ends, which hook projects transverse to the longitudinal axis of the strut, beyond its outer surface. With this hook the strut can be fastened into a recess of the perforated disk, in that the hook is inserted into and through the recess, in a position in which it projects downward, in the vertical direction, from top to bottom. A releasable wedge is provided at the same end of the strut, which wedge is displaceable relative to the hook, in the vertical direction. This wedge projects, before the hook is completely introduced into a recess of the perforated disk, downward and laterally beyond the contour of the hook, so that this wedge end comes to lie on an edge of the recess or on the top of the perforated disk in a region next to the recess, during vertical introduction of the hook, and whereby the wedge end is pushed upward and, at the same time, displaced in the transverse direction relative to the hook, all the way into a wedge position in which the said lower wedge end of the wedge can pass through the recesses and, after passing through the recess, can move laterally into a spread position, in which vertical or plumb-line movement of the strut end upward, through the recess, is blocked. The strut can be inserted into the recesses of the perforated disk fastened onto the pillar, proceeding from its end facing away from the scaffolding node, from above, vertically downward, whereby the wedge moves into its introduction position that allows introduction of the hook into the recess, by means of its impact on the edge section of the perforated disk that surrounds the recess. After the hook passes through the recess, the wedge automatically moves into a locking position, as the result of gravity, or as the result of a pressure or impact on its upper end, in which position it projects away from the hook profile to such an extent that in this spread position, hook and wedge cannot pass through the recess, and the wedge can only be moved out of this spread position by means of a force that acts on it, for example by means of a hammer blow from below onto the lower end of the wedge. In the case of this arrangement, the installer can first hang the strut into the recess with the hook, so that the strut is already provisionally held in this position, and the scaffolding section can be walked on, if necessary, and afterward, by pushing the strut end toward the pillar, in a horizontal direction, the wedge falls downward, for example as the result of gravity. In the transition phase, however, in which the strut is locked to the perforated disk only provisionally, by way of the hook inserted through a recess of the perforated disk, the strut can be lifted upward off the perforated disk again without hindrance. In the worst case, unintentional or accidental lift-off of the strut that is held in place only provisionally can occur. This represents a significant safety problem. Furthermore, this design and the related fastening procedure cannot be transferred to scaffolding components and methods for fastening them, as they are disclosed in the documents mentioned initially, or cannot be easily transferred.